Acoustic mine countermeasures

Abstract

A mine sweeping method and related apparatus for achieving at least tempoy passivation of underwater acoustic influence mines, by the generation of particular underwater sounds of progressively increasing intensity. The water is by repetitively injecting into the water individual metered slugs of heated water, which water is heated to its saturation pressure but below the critical point. The metered slugs of heated water may be of the same or of progressively increasing size, i.e. weight, and can be released from a heated pressure chamber into the water from either a stationary array or from an array towed from a moving ship, and at a depth such tht the expanding bubbles, produced by the change of state of the heated water, do not break the water surface. The rapid expansion of the metered slugs produce the desired sound output for temporarily rendering the acoustic influence mines passive by actuating their anticountermine circuits.

What is claimed is: 
     
       1. In the art of producing underwater sound in a body of water the herein described improvement which comprises the step of dispensing under water a slug of water heated to a temperature such that when suddenly exposed to the ambient pressure at least a portion of the water in the slug will flash into steam.   
     
     
       2. Apparatus for producing underwater acoustic signals in a body of water comprising a housing adapted to be submerged in said body of water,   an outlet port in said housing adapted to be submerged when said housing is submerged,   a pressure chamber in said housing adapted to contain water,   means for heating water in said pressure chamber to a high temperature, and   metering means operative to dispense a measured slug of water from said pressure chamber through said outlet port.   
     
     
       3. Apparatus in accordance with claim 2 wherein said metering means is operative in one operating cycle to dispense through said outlet port a series of slugs of water of progressively increased weight. 
     
     
       4. Apparatus in accordance with claim 3 wherein said metering means includes a rotatably mounted circular drum,   a plurality of wells formed in said drum in spaced relation along a circumference of said drum, said wells progressively increasing in volume in one direction along said circumference, and   a portion of said circumference being in constant communication with said pressure chamber,     means for rotating said drum in the direction opposite to said one direction whereby said wells serially aline themselves with said outlet port, and   means responsive to the angular position of said drum for stopping its rotation after the largest of said wells has alined with said outlet port and before the smallest of said wells has lost communication with said pressure chamber.   
     
     
       5. Apparatus in accordance with claim 4 and wherein a valve means operable in timed relation with the rotation of said drum functions to open said outlet port only when one of said wells is in substantial alinement with said outlet port.